Antenna Selection for Wi-Fi Deployments Topics: . Antenna functionality . Antenna specifications . Antenna types . Internal vs. external . Coverage patterns . Bridge links 1 Certified Wireless Network Professional Understanding Antennas Electromagnetic Waves Antennas radiate electromagnetic waves into the air Antennas both radiate and receive electromagnetic waves. They radiate the waves as the electromagnetic signal escapes from the antenna. They receive waves as the energy is captured by the antenna. 2 Certified Wireless Network Professional Active vs. Passive Gain Amplifier Passive gain uses no extra Active gain uses an RF amplifier to amplification and relies fully on increase the signal strength. The the directionality of the amplifier is placed in path between antenna for increased RF the AP and antenna or between energy in a desired direction. the radio and antenna. 3 Certified Wireless Network Professional SISO vs. MIMO Single Input/Single Output Multiple Input/Multiple Output 4 Certified Wireless Network Professional dBi Gain compared to an isotropic radiator (dBi) -50 dB point Isotropic Isotropic Radiator Radiator -48 dB point 2 dBi Antenna -50 dB point 5 Certified Wireless Network Professional Antenna Specifications Key Specifications . Frequency . Resistance (Ohms) . Gain . Connector type . Beamwidth 6 Certified Wireless Network Professional RF Radiation Patterns Patch Antenna Omni Antenna Internal AP Antenna 7 Certified Wireless Network Professional Antenna Charts Elevation (Vertical) Azimuth (Horizontal) 8 Certified Wireless Network Professional Elevation and Azimuth Charts Illustrated Azimuth (Horizontal) Elevation (Vertical) 9 Certified Wireless Network Professional Antenna Types Omnidirectional Patch Dish Semi-Directional Highly Directional 10 Certified Wireless Network Professional Internal vs. External Antennas Internal antennas work well for common office space deployments. External antennas work well for coverage of large areas or when directionality is needed. 11 Certified Wireless Network Professional Environmental Impact on Radiation Patterns Materials and objects in the environment will change the radiation pattern in actual space from that specified for the antenna. 12 Certified Wireless Network Professional WLAN Coverage Coverage factors: . Radiation patterns . Output power Warehouse Coverage . RF behaviors Office Coverage 13 Certified Wireless Network Professional Outdoor Coverage Semi-directional antennas are used in this case to radiate out from the building. 14 Certified Wireless Network Professional Bridge Links Factors: . Link Budget . Required Data Rate . Link Quality Free Space Path Loss Line of Sight Clearance 15 Certified Wireless Network Professional.